Apple Inc. (Nasdaq:AAPL - news) is throwing its weight behind the music industry’s efforts to protect the album format by allowing fans to buy complete digital albums without having to pay again for songs they already own.

[...] Apple said on Thursday iTunes is introducing a “Complete My Album” service that offers customers who want to turn individual tracks into an album a 99-cent credit for every song they have already purchased from the album.

For example, if a customer had bought three 99-cent singles and decides to download the entire album with a listed price of $9.99, the customer would only have to pay $7.02.

Fans will only be able to take advantage of the discount within 180 days after first buying the songs, Apple said.

Is CRM coming to popular culture? Does American Idol discover real artists? A look at what a blend of radio and the Internet can be: A Radio Station Just for You

At signup, the service asks users to download software â€” available for Macs and PCs â€” that tracks the music playing on your computer. The song-counting process, called â€œscrobblingâ€ by Last.fmâ€™s chief software developer, lets the company observe shifts in popularity, spot unexpected correlations between songs, and even discover new artists â€” or new tracks by known artists.

To date, Last.fm has â€œscrobbledâ€ 65 million tracks by 8 million artists, in just about every country in the world. As with Pandora, you can identify songs you love, which helps to tailor your radio experience. The result is a stream of music that, statistically speaking, you ought to enjoy.

[...] The royalty issue is explicitly why services like Soundflavor, Goombah and Mog donâ€™t offer true streaming radio. Soundflavor DJ, a free player available at www.soundflavor.com, uses a collaborative filtering technique, but instead of streaming new songs, it lets you cue up songs on iTunes or Windows Media Player, then takes over D.J. responsibility, matching your initial choices with other tracks from your own collection. It is especially effective if you have a library with thousands of tracks. After every few songs, Soundflavor offers you a free track download from an independent artist, or the opportunity to buy a song that its filter suggests you might like.